Process for mineral carbonation with carbon dioxide

Abstract

A process for mineral carbonation with carbon dioxide wherein carbon dioxide is reacted with a bivalent alkaline earth metal silicate, selected from the group of ortho-, di-, ring, and chain silicates, which silicate is immersed in an aqueous electrolyte solution. The invention further relates to the use of the mixture of carbonate and silica formed in such a process in construction materials and to the use of the carbonate formed by such a process for the production of calcium oxide.

1 . A process for mineral carbonation with carbon dioxide wherein carbon dioxide is reacted with a bivalent alkaline earth metal silicate, selected from the group of ortho-, di-, ring, and chain silicates, which silicate is immersed in an aqueous electrolyte solution.  
     
     
         2 . A process according to  claim 1 , wherein silicates particles are dispersed in the aqueous electrolyte solution.  
     
     
         3 . A process according to  claim 2 , wherein the silicate particles have an average diameter of at most 5 mm, preferably at most 1 mm, more preferably at most 0.2 mm.  
     
     
         4 . A process according to  claim 2  or  3 , wherein the silicate particles are mechanically treated such that their size is reduced during the process.  
     
     
         5 . A process according to  claim 4 , which is an extrusion process.  
     
     
         6 . A process according to any one of the preceding claims, wherein the electrolyte is a salt having a solubility in water of at least 0.01 moles per litre, preferably at least 0.1 moles per litre.  
     
     
         7 . A process according to  claim 6 , wherein the electrolyte is a sodium, potassium or barium salt, more a chloride or nitrate of sodium, potassium or barium, even more preferably sodium nitrate.  
     
     
         8 . A process according to any one of the preceding claims, wherein the concentration of electrolyte in the electrolyte solution is at least 0.01 moles per litre, preferably in the range of from 0.1 to 2 moles per litre.  
     
     
         9 . A process according to any one of the preceding claims, wherein the bivalent alkaline earth metal silicate is a magnesium or calcium silicate.  
     
     
         10 . A process according to  claim 9 , wherein the silicate is a calcium silicate and the operating temperature is in the range of from 20 to 400° C., preferably of from 80 to 300° C., more preferably of from 100 to 200° C.  
     
     
         11 . A process according to  claim 9 , wherein the silicate is a magnesium silicate and the operating temperature is in the range of from 20 to 250° C., preferably of from 100 to 200° C.  
     
     
         12 . A process according to any one of the preceding claims, wherein the operating pressure is in the range of from 1 to 150 bar (absolute), preferably of from 1 to 75 bar (absolute).  
     
     
         13 . Use of the mixture of silica and carbonate formed by the process according of any one of the preceding claims in construction materials.  
     
     
         14 . A process according to any one of  claims 1  to  12  further comprising mixing the mixture of silica and carbonate formed with a molten binder and solidifying the silica/carbonate/binder mixture a construction material.  
     
     
         15 . A process according to  claim 14 , wherein the binder is a hydrocarbonaceous binder.  
     
     
         16 . Use of the carbonate formed by the process according of any one of  claims 1  to  12  for the production of calcium oxide.